Power to Gas

30th November 2018

Dave Elliott: Hydrogen gas made via the electrolysis of water using surplus renewable electricity can be stored then used when needed for power production, heating, industry and in vehicles. It’s an ideal multi-purpose fuel; it only produces water, and some NOx, when burnt in air or used in a fuel cell to re-generate electricity. And now this power to gas (P2G) approach is becoming cheaper. Perhaps the most exciting prospect is that P2G offers a way to balance variable renewables. Indeed, it turns their variability into a solution rather than a problem. In order to meet demand most of the time, at non-peak demand times a power system based on renewables would be likely to have substantial overcapacity, so that there would be surplus renewables output. If that can be converted to storable hydrogen, it can be used to generate power later, when renewable supplies are low and power demand high. Since there could be a lot of this hydrogen, some of it could also offset fossil gas use, by being injected into the gas grid, possibly after conversion into methane. In addition, some of the hydrogen or methane could be used as a vehicle fuel. It all sounds wonderful, but is P2G really viable at scale? A recent report on green heating options from the UK’s Climate Change Committee (CCC) was unconvinced, but there are other views. So, despite the CCC’s reservations, P2G does look promising. Some say that, with renewable costs falling, we may reach the point where P2G becomes fully competitive. A recent study for Greenpeace Energy by Berlin-based Energy Brainpool claimed that hydrogen from surplus renewables will be cheaper than gas in the 2030s. It cites the International Energy Agency view that natural gas prices are set to rise steadily until the 2040s, from €0.017/kWh in 2020 to €0.032/kWh by 2030 and €0.041/kWh by 2040. By contrast, IEA analysts forecast that production costs for hydrogen generated by wind power are set to fall from “about €0.18/kWh” to €0.13/kWh by 2020, to €0.12/kWh by 2030, and to between €0.021/kWh and €0.032/kWh by 2040. As I have noted in earlier posts, there are other approaches. For example, the Leeds H21 100% hydrogen heating project is getting some support. But it is focused on SMR using fossil gas with CCS — P2G has been relegated to a possible longer-term option. However, the case for P2G is building up, not least since, unlike the H21 plan, it doesn’t need costly and uncertain CCS, and can deliver fully carbon-neutral hydrogen.

Clients have included Greenpeace, Nuclear Free Local Authorities, WWF Scotland and the UK Government’s Committee on Radioactive Waste Management.

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